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This paper presents a C-band single linear polarization reconfigurable phase-shifting cell. It consists of five rectangular coupled slots loaded with one variable capacitance in order to control the reflected phase. This variable capacitance is modelled with a lumped element, typically representing a surface mount varactor diode. A biasing line is also considered to isolate the RF signal from DC. Simulations demonstrate the superiority of this unit cell to its counterparts in terms of phase-range, bandwidth and robustness against oblique angle of incidence. In addition, numerical results show the ability of the unit cell to tilt the main beam of a circular array by 25° off broadside direction.

It has been observed that an alarming rate of road accidents occur in different countries every year with the increase of bikes and motorcycles. Some countries are one of the densely populated in the world where roads are narrower in comparison to the roads and streets. Although enough rules and regulations are made by the government to avoid road accidents, but the accident rate is increasing day by day. Reasons such as avoiding helmet by the bike rider during their ride as well as riding being drunk are worth mentionable. Motorcycle rider involve them in serious road accidents causing fatality while not wearing helmet and riding motorcycles being drunk. Wearing helmet can however reduce the risk of accidents largely. In this paper a very effective and technological way of Smart Helmet using Internet of Things (IoT) has been introduced by which one can avoid such problems. Arduino NANO and Arduino Mega-2560 are microcontrollers which control the entire components of the system. Two 2.4 GHZ nRF24L01 acts like sender and receiver for communication. One MQ-3 gas sensor is used which can detect whether the bike rider is alcoholic or not. If the bike rider is alcoholic, then the MQ-3 sensor detects it and the whole system goes off. A Sharp IR sensor detects the head of the motorcyclist within the range of 10–80 cm. The Bike rider's engine will start only when the rider will buckle the helmet. GPS & GSM Technology is used for tracking the location of the bike rider and sending text message to the family members of the Bike rider when an accident occurs. Our Smart Helmet is used for Accident Detection and Bike Rider's Safety.

This article investigates how beam steering makes the antenna intelligent by increasing channel capacity, range, and reducing interference to enhance the gain of a rectangular patch array antenna for the 5G application using a novel double negative metamaterial (DNG). Beam-steering antennas are the ideal solution for a variety of system applications; it is mostly achieved using phased arrays, where phase shifters are used to control the main-beam. In this paper, the pin-diode phase shifters were considered. ”ON” and ”OFF” states provide phase shift due to different current paths. The main beam direction can be switched between the angles of 25 degrees with a 3dB beamwidth of 23 degrees. The metamaterial structure is composed of 8x8 mm on Rogers RT/duroid 5880 with 0. 254mm thickness and dielectric constant of 2.2. The proposed phase array antenna has four microstrip patch with a thickness of 0. 0175mm printed on the same Rogers RT-duroid substrate with a dielectric constant of 2.2 with dimensions of 5.40 mm x3.94 mm. The phased array antenna without metamaterial structure presented a directivity of 14. 8dBi.Gain increase to 16. 6dBi upon placing the metamaterial structure at a distance 24. 3mm.

This paper presents a novel analysis of a C-shaped thickness of metamaterial unit cell structure that is applicable in a multi-band frequency range, which exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate rectangular resonator is inserted into a bigger split-resonator in a form of C-shape at a gap of 20mm to form a unit structure. Analysis and a comparison of the thickness of 0.1mm, 0.5mm, 1mm, 1.5mm and 2mm unit cell configurations were performed. These configurations demonstrate multi-band operational frequencies with double-negative characteristics. Equivalent circuit model and measured result for each unit cell validate the resonant behaviour. Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a unique and promising invention in the electromagnetic model for its double-negative characteristics, simplicity and multi-band operation

The layout of this research work is to simulate a novel combination of C and U-shape unit cell at resonance frequency of 28 GHz for 5G operation, having negative permittivity and permeability which is often referred to as double negative metamaterial (DNG) or left-handed material. The DNG shape includes C and U resonators on one side of dielectric medium and a wire on other side. The Scattering parameters as well as permittivity, permeability and refractive index are determined from the simulated Simulations of DNG structure using Computer simulation technology (CST) in microwave studio (MWS). For verification of negative values of structure’s parameter, MATLAB was used. This is a novel and promising design approach in the world of electromagnetics due to its simplicity, scalability and characteristics of double-negative material.

This paper describes the design and analysis of a multi-resonant compact patch antenna with fractal slots on the basis of Smith Chart geometry for indoor communication systems. A 60mm × 60mm × 1mm single patch antenna with periodic fractals in the form of combined r and x circles is capable of resonating at some desired sub-bands starting from LTE to WI-MAX with good enough directional characteristics greater than 3 dB in average within the whole frequency band. The dielectric material used for the proposed Microstrip patch antenna is Rogers TMM4 with dielectric constant of 4.5 and the patch is made up of perfect electric conductor (PEC). The proposed fractal geometry possesses multiband behavior at 0.7 GHz, 1.15 GHz, 1.8 GHz, 2.4 GHz, 3.7 GHz, 5.2 GHz and 5.8 GHz. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably shown better performance and supplementary compactness which makes it competitive among other antenna models.